The actors did most of their stunts, even driving down the stairs in the LA Metro.
In interviews, Jason Statham said that in addition to the stunt driving course they all received, he got two days' driving tuition from Damon Hill, the British ex-world champion Formula 1 driver. However, all of the cast members acknowledged that Charlize Theron was easily the best driver among them.
There were no visual effects used for the scene with the helicopter.
The principal actors in the movie did most of the stunt driving themselves. While all of the principals needed stunt driving lessons, Yasiin Bey aka Mos Def, who is from New York City, needed a little more work because he didn't have a driver's license at the onset of production.
During production, Charlize Theron got two speeding tickets while driving in her own car, both for going more than 40 miles per hour over the speed limit. She said that after filming driving so fast, she just couldn't get her speed down to drive home.